Showing Thornyhold by Mary Stewart

Thornyhold is a house deep in a wild wood like somewhere out of a fairy tale. To Gilly, it is an enchantment. Her very own enchantment, left to her by the cousin whose occasional magical visits had brightened her childhood. And as she explores, she discovers more about the woman who had come to seem like a fairy godmother for her: her herbalists's skills, her still room, her abilities to foresee and to heal. She discovers also that the local people believe that Gilly has inherited not just the house but the magical spell-weaving powers that live on in the house and garden. Slowly, quietly, she comes to realise that they are right.